A convertible buccal tube is an appliance used by orthodontists during an early phase of treatment to correct malpositioned teeth. The tube is essentially an orthodontic bracket in which the buccal or cheek-facing side of the usual arch-wire slot is closed by a plate to form a tubular opening of typically rectangular cross section. The plate is brazed or spot-welded in place, and can be removed to convert the buccal tube to a conventional bracket during later stages of treatment.
Convertible buccal tubes have been in use for many years, and reference is made to U.S. Pat. No. 3,391,461 for further background information. Tubes of this type are normally used on younger children whose second molars have not yet grown in, but who have erupted first molars which serve as anchor teeth for an orthodontic arch wire. The covered arch-wire slot provides a terminal buccal-tube anchorage for the arch wire during early treatment.
When the second molars erupt, these newly emerged teeth are provided with banded brackets which take over the "anchor" function and receive the terminal ends of a longer arch wire. Prior to installation of the longer arch wire, the arch-wire cover plate on each first-molar tube is removed to convert the tube to a conventional molar bracket, and thus to enable normal edgewise treatment of the first molars. An improved tool to remove the cover plate is shown in my U.S. Pat. No. 4,669,979.
Known convertible buccal tubes are of two-piece construction (bracket and cover plate), and production expense is increased by the necessary welding, brazing or other attachment process for securing the plate to the appliance body. These known units also sometimes present cover-plate removal problems in that the plate may be awkward and difficult to sever from the underlying body.